Applications & Pathways
Implementation of Fuel Cells in Aviation from a Maintenance, Repair and Overhaul Perspective
Dec 2022
Publication
Hydrogen is one of the most promising power sources for meeting the aviation sector’s long-term decarbonization goals. Although on-board hydrogen systems namely fuel cells are extensively researched the maintenance repair and overhaul (MRO) perspective remains mostly unaddressed. This paper analyzes fuel cells from an MRO standpoint based on a literature review and comparison with the automotive sector. It also examines how well the business models and key resources of MRO providers are currently suited to provide future MRO services. It is shown that fuel cells require extensive MRO activities and that these are needed to meet the aviation sector’s requirements for price safety and especially durability. To some extent experience from the automotive sector can be built upon particularly with respect to facility requirements and qualification of personnel. Yet MRO providers’ existing resources only partially allow them to provide these services. MRO providers’ underlying business models must adapt to the implementation of fuel cells in the aviation sector. MRO providers and services should therefore be considered and act as enablers for the introduction of fuel cells in the aviation industry.
An Inter-laboratory Comparison between 13 International Laboratories for Eight Components Relevant for Hydrogen Fuel Quality Assessment
Mar 2024
Publication
The quality of the hydrogen delivered by refuelling stations is critical for end-users and society. The purity of the hydrogen dispensed at hydrogen refuelling points should comply with the technical specifications included in the ISO 14687:2019 and EN 17124:2022 standards. Once laboratories have set up methods they need to verify their performances for example through participation in interlaboratory comparisons. Due to the challenge associated with the production of stable reference materials and transport of these which are produced in hydrogen at high pressure (>10 bar) interlaboratory comparisons have been organized in different steps with increasing extent. This study describes an inter-laboratory comparison exercise for hydrogen fuel involving a large number of participants (13 laboratories) completed in less than a year and included eight key contaminants of hydrogen fuel at level close to the ISO14687 threshold. These compounds were selected based on their high probability of occurrence or because they have been found in hydrogen fuel samples. For the results of the intercomparison it appeared that fully complying with ISO 21087:2019 is still challenging for many participants and highlighted the importance of organising these types of exercises. Many laboratories performed corrective actions based on their results which in turn significantly improved their performances.
Research on the Adaptability of Proton Exchange Membrane Electrolysis in Green Hydrogen-Electric Coupling System Under Multi-operating Conditions
Mar 2023
Publication
The green hydrogen–electric coupling system can consume locally generated renewable energy thereby improving energy utilization and enabling zero-carbon power supply within a certain range. This study focuses on a green hydrogen–electric coupling system that integrates photovoltaic energy storage and proton exchange membrane electrolysis (PEME). Firstly the impact of operating temperature power quality and grid auxiliary services on the characteristics of the electrolysis cell is analyzed and a voltage model and energy model for the cell are established. Secondly a multi-operating conditions adaptability experiment for PEME grid-connected operation is designed. A test platform consisting of a grid simulator simulated photovoltaic power generation system lithium battery energy storage system PEME and measurement and acquisition device is then built. Finally experiments are conducted to simulate multi-operating conditions such as temperature changes voltage fluctuations frequency offsets harmonic pollution and current adjustment speed. The energy efficiency and consumption is calculated based on the recorded data and the results are helpful to guide the operation of the system.
Increasing Technical Efficiency of Renewable Energy Sources in Power Systems
Mar 2023
Publication
This paper presents a method for refining the forecast schedule of renewable energy sources (RES) generation by its intraday adjustment and investigates the measures for reserving RES with unstable generation in electric power systems (EPSs). Owing to the dependence of electricity generation by solar and wind power plants (PV and WPPs respectively) on natural conditions problems arise with their contribution to the process of balancing the power system. Therefore the EPS is obliged to keep a power reserve to compensate for deviations in RES from the planned generation amount. A system-wide reserve (mainly the shunting capacity of thermal and hydroelectric power plants) is used first followed by other means of power reserve: electrochemical hydrogen or biogas plants. To analyze the technical and economic efficiency of certain backup means mathematical models based on the theory of similarity and the criterion method were developed. This method is preferred because it provides the ability to compare different methods of backing up RES generation with each other assess their proportionality and determine the sensitivity of costs to the capacity of backup methods with minimal available initial information. Criterion models have been formed that allow us to build dependencies of the costs of backup means for unstable RES generation on the capacity of the backup means. It is shown that according to the results of the analysis of various methods and means of RES backup hydrogen technologies are relatively the most effective. The results of the analysis in relative units can be clarified if the current and near-term price indicators are known.
Low Carbon Optimal Operation of Integrated Energy System Based on Concentrating Solar Power Plant and Power to Hydrogen
Mar 2023
Publication
A new integrated energy system (IES) framework is created in order to encourage the consumption of renewable energy which is represented by wind and solar energy and lower carbon emissions. The connection between the units in the composite system is examined in this research. In-depth analysis is done on how energy is transferred between electricity heat gas and hydrogen. The system model and constraints are used to build an objective function with the lowest total operating cost. The calculation of carbon trading includes the ladder carbon trading method. And set up 6 cases for analysis which verifies the effectiveness of the participation of the concentrated solar power plant (CSPP) in the heat supply and power to hydrogen system (P2HS) in reducing the total operating cost of the system reducing wind curtailment and light curtailment and reducing carbon emissions. Under the model considered in this paper reduces the total operating cost reduces by 27.04% when the concentrated solar power plant is involved in the supply of thermal load. And the carbon emission is reduced by 14.529%. Compared with the traditional power to gas considers the power to hydrogen system in this paper which reduces the total operating cost by 4.79%.
Green Hydrogen Value Chain: Modelling of a PV Power Plant Integrated with H2 Production for Industry Application
Mar 2024
Publication
Based on the Sustainable Development Goals outlined in the 2030 agenda of the United Nations affordable and clean energy is one of the most relevant goals to achieve the decarbonization targets and break down the global climate change effects. The use of renewable energy sources namely solar energy is gaining attention and market share due to reductions in investment costs. Nevertheless it is important to overcome the energy storage problems mostly in industrial applications. The integration of photovoltaic power plants with hydrogen production and its storage for further conversion to usable electricity are an interesting option from both the technical and economic points of view. The main objective of this study is to analyse the potential for green hydrogen production and storage through PV production based on technical data and operational considerations. We also present a conceptual model and the configuration of a PV power plant integrated with hydrogen production for industry supply. The proposed power plant configuration identifies different pathways to improve energy use: supply an industrial facility supply the hydrogen production and storage unit sell the energy surplus to the electrical grid and provide energy to a backup battery. One of the greatest challenges for the proposed model is the component sizing and water electrolysis process for hydrogen production due to the operational requirements and the technology costs.
Refuelling Infrastructure Requirements for Renewable Hydrogen Road Fuel through the Energy Transition
Nov 2022
Publication
Current commercially available options for decarbonisation of road transport are battery electric vehicles or hydrogen fuel cell electric vehicles. BEVs are increasingly deployed while hydrogen is in its infancy. We examine the infrastructure necessary to support hydrogen fuelling to various degrees of market penetration. Scotland makes a good exemplar of transport transition with a world leading Net-Zero ambition and proven pathways for generating ample renewable energy. We identified essential elements of the new transport systems and the associated capital expenditure. We developed nine scenarios based on the pace of change and the ultimate market share of hydrogen and constructed a model to analyse their infrastructure requirements. This is a multi-period model incorporating Monte Carlo and Markov Chain elements. A “no-regrets” initial action is rapid deployment of enough hydrogen infrastructure to facilitate the early years of a scenario where diesel fuel becomes replaced with hydrogen. Even in a lower demand scenario of only large and heavy goods vehicles using hydrogen the same infrastructure would be required within a further two years. Subsequent investment in infrastructure could be considered in the light of this initial development.
Comprehensive Analysis of the Operation of an Internal Combustion Engine Fueled by Hydrogen-containing Mixtures
Mar 2023
Publication
At present hydrogen is considered as one of the most promising motor fuels capable of replacing traditional hydrocarbons. This article presents the results of a comprehensive experimental study of the effect of hydrogen additives on the main parameters of a gasoline spark-ignition ICE. The thermophysical parameters of the processes of ignition and combustion inside the cylinder with the addition of hydrogen in the amount of 0%–20% of the air volume as well as the fuel and energy characteristics of the engine and its impact on the environment were studied. It has been established that hydrogen leads to significant changes in the engine operation. It increases some parameters and reduces others improving or worsening them compared to running on pure gasoline. So with a 20% H2 addition at an average engine load the following parameters increase: the maximum pressure in the cylinder by almost 20%; the rate of pressure increase in the combustion chamber by 2.8 times; the highest combustion temperature by 140 K. At the same time the following parameters decrease: average indicator pressure by 18%; ignition timing by 82% (6◦ to TDC versus 34◦ for gasoline); crank angle corresponding to the maximum pressure by 32% (9.4◦ versus 13.9◦ for gasoline); crank angle corresponding to maximum temperature by 54% (17.7◦ after TDC versus 38.3◦ for clean gasoline); ignition delay time (τind = 0.32 ms) and visible combustion time (τvis = 1.58 ms) by 4 and 2.3 times respectively.
Towards a Prioritization of Alternative Energy Sources for Sustainable Shipping
Apr 2023
Publication
Studies on the prospects of the use of alternative fuels in the maritime industry have rarely been assessed in the context of developing countries. This study assesses seven energy sources for shipping in the context of Bangladesh with a view to ranking their prospects based on sustainability as well as identifying the energy transition criteria. Data were collected from maritime industry experts including seafarers shipping company executives government representatives and academics. The Bayesian Best-Worst Method (BWM) was used for ranking nine criteria related to the suitability and viability of the considered alternative energy sources. Next the PROMETHEE-GAIA method is applied for priority analysis of the seven energy alternatives. The findings reveal that capital cost alternative energy price and safety are the most important factors for alternative energy transition in Bangladesh. Apart from the benchmark HFO Liquified Natural Gas (LNG) HFO-Wind and LNG-Wind hybrids are considered the most viable alternatives. The findings of the study can guide policymakers in Bangladesh in terms of promoting viable energy sources for sustainable shipping.
Economic Evaluation of a Power-to-hydrogen System Providing Frequency Regulation Reserves: A Case Study of Denmark
Mar 2023
Publication
Operating costs are dominant in the hydrogen production of a power-to-hydrogen system. An optimal operational strategy or bidding framework is effective in reducing these costs. However it is still found that the production cost of hydrogen is high. As the electrolysis unit is characterized by high flexibility providing ancillary service to the grid becomes a potential pathway for revenue stacking. Recent research has demonstrated the feasibility of providing such a service but the related economics have not been well evaluated. In this work we propose a comprehensive operation model to enable participation in the day-head balancing and reserve markets. Three types of reserves are considered by using different operational constraints. Based on the proposed operation framework we assess the economic performance of a power-to-hydrogen system in Denmark using plentiful actual market data. The results reveal that providing frequency containment reserve and automatic frequency restoration reserve efficiently raises the operational contribution margins. In parallel by investing in the cash flows net present value and break-even hydrogen prices we conclude that providing reserves makes the power-to-hydrogen project more profitable in the studied period and region.
Reduction of Iron Oxides with Hydrogen - A Review
Aug 2019
Publication
This review focuses on the reduction of iron oxides using hydrogen as a reducing agent. Due to increasing requirements from environmental issues a change of process concepts in the iron and steel industry is necessary within the next few years. Currently crude steel production is mainly based on fossil fuels and emitting of the climate-relevant gas carbon dioxide is integral. One opportunity to avoid or reduce greenhouse gas emissions is substituting hydrogen for carbon as an energy source and reducing agent. Hydrogen produced via renewable energies allows carbon-free reduction and avoids forming harmful greenhouse gases during the reduction process. The thermodynamic and kinetic behaviors of reduction with hydrogen are summarized and discussed in this review. The effects of influencing parameters such as temperature type of iron oxide grain size etc. are shown and compared with the reduction behavior of iron oxides with carbon monoxide. Different methods to describe the kinetics of the reduction progress and the role of the apparent activation energy are shown and proofed regarding their plausibility.
Power Scheduling Optimization Method of Wind-Hydrogen Integrated Energy System Based on the Improved AUKF Algorithm test2
Nov 2022
Publication
With the proposal of China’s green energy strategy the research and development technologies of green energy such as wind energy and hydrogen energy are becoming more and more mature. However the phenomenon of wind abandonment and anti-peak shaving characteristics of wind turbines have a great impact on the utilization of wind energy. Therefore this study firstly builds a distributed wind-hydrogen hybrid energy system model then proposes the power dispatching optimization technology of a wind-hydrogen integrated energy system. On this basis a power allocation method based on the AUKF (adaptive unscented Kalman filter) algorithm is proposed. The experiment shows that the power allocation strategy based on the AUKF algorithm can effectively reduce the incidence of battery overcharge and overdischarge. Moreover it can effectively deal with rapid changes in wind speed. The wind hydrogen integrated energy system proposed in this study is one of the important topics of renewable clean energy technology innovation. Its grid-connected power is stable with good controllability and the DC bus is more secure and stable. Compared with previous studies the system developed in this study has effectively reduced the ratio of abandoned air and its performance is significantly better than the system with separate grid connected fans and single hydrogen energy storage. It is hoped that this research can provide some solutions for the research work on power dispatching optimization of energy systems.
Renewable Electricity for Decarbonisation of Road Transport: Batteries or E-Fuels?
Feb 2023
Publication
Road transport is one of the most energy-consuming and greenhouse gas (GHG) emitting sectors. Progressive decarbonisation of electricity generation could support the ambitious target of road vehicle climate neutrality in two different ways: direct electrification with onboard electro-chemical storage or a change of energy vector with e-fuels. The most promising state-of-the-art electrochemical storages for road transport have been analysed considering current and future technologies (the most promising ones) whose use is assumed to occur within the next 10–15 years. Different e-fuels (e-hydrogen e-methanol e-diesel e-ammonia E-DME and e-methane) and their production pathways have been reviewed and compared in terms of energy density synthesis efficiency and technology readiness level. A final energetic comparison between electrochemical storages and e-fuels has been carried out considering different powertrain architectures highlighting the huge difference in efficiency for these competing solutions. E-fuels require 3–5 times more input energy and cause 3–5 times higher equivalent vehicle CO2 emissions if the electricity is not entirely decarbonised.
Fuel Cells for Shipping: To Meet On-board Auxiliary Demand and Reduce Emissions
Feb 2021
Publication
The reduction of harmful emissions from the international shipping sector is necessary. On-board energy demand can be categorised as either: propulsion or auxiliary services. Auxiliary services contribute a significant proportion of energy demand with major loads including: compressors pumps and HVAC (heating ventilation and air-conditioning). Typically this demand is met using the same fuel source as the main propulsion (i.e. fossil fuels). This study has analysed whether emissions from large scale ships could feasibly be reduced by meeting auxiliary demand by installing a hydrogen fuel cell using data from an LNG tanker to develop a case study. Simulations have shown that for a capacity of 10 x 40ft containers of compressed hydrogen the optimal fuel cell size would be 3 MW and this could save 10600 MWh of fossil fuel use equivalent to 2343 t of CO2. Hence this could potentially decarbonise a significant proportion of shipping energy demand. Although there are some notable technical and commercial considerations such as fuel cell lifetime and capital expenditure requirements. Results imply that if auxiliary loads could be managed to avoid peaks in demand this could further increase the effectiveness of this concept.
Assessing the Performance of Fuel Cell Electric Vehicles Using Synthetic Hydrogen Fuel
Mar 2024
Publication
The deployment of hydrogen fuel cell electric vehicles (FCEVs) is critical to achieve zero emissions. A key parameter influencing FCEV performance and durability is hydrogen fuel quality. The real impact of contaminants on FCEV performance is not well understood and requires reliable measurements from real-life events (e.g. hydrogen fuel in poor-performing FCEVs) and controlled studies on the impact of synthetic hydrogen fuel on FCEV performance. This paper presents a novel methodology to flow traceable hydrogen synthetic fuel directly into the FCEV tank. Four different synthetic fuels containing N2 (90–200 µmol/mol) CO (0.14–5 µmol/mol) and H2S (4–11 nmol/mol) were supplied to an FCEV and subsequently sampled and analyzed. The synthetic fuels containing known contaminants powered the FCEV and provided real-life performance testing of the fuel cell system. The results showed for the first time that synthetic hydrogen fuel can be used in FCEVs without the requirement of a large infrastructure. In addition this study carried out a traceable H2 contamination impact study with an FCEV. The impact of CO and H2S at ISO 14687:2019 threshold levels on FCEV performance showed that small exceedances of the threshold levels had a significant impact even for short exposures. The methodology proposed can be deployed to evaluate the composition of any hydrogen fuel.
Drop-in and Hydrogen-based Biofuels for Maritime Transport: Country-based Assessment of Climate Change Impacts in Europe up to 2050
Nov 2022
Publication
Alternative fuels are crucial to decarbonize the European maritime transport but their net climate benefits vary with the type of fuel and production country. In this study we assess the energy potential and climate change mitigation benefits of using agricultural and forest residues in different European countries for drop-in (Fast Pyrolysis Hydrothermal Liquefaction and Gasification to Fischer-Tropsch fuels or Bio-Synthetic Natural Gas) and hydrogen-based biofuels (hydrogen ammonia and methanol) with or without carbon capture and storage (CCS). Our results show the combinations of countries and biofuel options that successfully achieve the decarbonization targets set by the FuelEU Maritime initiative for the next years including a prospective analysis that include technological changes projected for the biofuel supply chains until 2050. With the current technologies the largest greenhouse gas (GHG) mitigation potential per year at a European scale is obtained with bio-synthetic natural gas and hydrothermal liquefaction. Among carbon-free biofuels ammonia currently has higher mitigation but hydrogen can achieve a lower GHG intensity per unit of energy with the projected decarbonization of the electricity mixes until 2050. The full deployment of CCS can further accelerate the decarbonization of the maritime sector. Choosing the most suitable renewable fuels requires a regional perspective and a transition roadmap where countries coordinate actions to meet ambitious climate targets.
Hydrogen or Hydrogen-derived Methanol for Dual-fuel Compression-ignition Combustion: An Engine Perspective
Oct 2022
Publication
Synthetic fuels or e-fuels produced from captured CO2 and renewable hydrogen are envisaged as a feasible path towards a climate-neutral transportation in medium/heavy-duty and maritime sectors. EU is presently debating energy targets by 2030 for these fuels. As their production involves chemical processing of hydrogen it must be evaluated if the extra cost is worthy at least in applications where hydrogen use is possible. This manuscript focuses on the performance and environmental impact when hydrogen and methanol are fed to a heavy-duty compression-ignition engine working under dual-fuel combustion. The trade-off thermal efficiency-NOx emissions is primary considered in the assessment by combining both variables in an own defined function. During the work engine operating settings were adjusted to exploit the potential of methanol and hydrogen. Compared to conventional combustion methanol required centering the combustion towards TDC and doubling the EGR rate resulting in a low temperature highly premixed combustion almost soot-free and with extremely low NOx emissions. The best settings for hydrogen were in the middle of those for methanol and conventional combustion. Results showed great dependance with the engine load but methanol proved superior to hydrogen for all conditions. At high load 20–60 % methanol even improved the efficiency and reduced the NOx emissions obtained by conventional combustion. However at low load hydrogen could substitute 90 % of the diesel fuel while methanol failed at substitutions higher than 55 %.
Pre-cooling Systems for Hydrogen Fueling Stations: Techno-economic Analysis for Scaled Enactment
Mar 2023
Publication
Hydrogen fueling standards stipulates a sustainable cooling system technically and economically. Accordingly the interior surface temperature of the on-board H2 storage tank in fuel cell electric vehicles must not exceed the maximum specified limit (358.15 K) and the fueling rate must be ≤ 42.86 sec / kg-H2 with T40 dispenser at 70 MPa. In this context H2 refueling stations often employ double-tube and block heat exchangers for heat transfer. This study examines the H2 pre-cooling system for various loads and provides a comparative techno-economic analysis of double tube heat exchangers (DTHE) and microchannel heat exchangers (MCHE) under stipulated technical operational and outlet gas standards. For this purpose thermal and hydraulic performances were simulated using ANSYS-CFX. Technical and cost models utilize manufacturer specifications and literature-based technical and economic characteristics to derive the minimum sustainable price defined as the price to sustain the product. The results showed that the MCHE outperformed the DTHE for setups in mass manufacturing improved effective heat transfer area and predicted long term unit cost. The annual quantitative output affects manufacturing expenses and profit margins substantially. With high production rates it is expected that the unit cost of the MCHE will decrease by up to 74%. In switching from DTHE to MCHE general material requirements decreased by ~60% with scrap waste savings of ~45% reflecting an appreciable footprint reduction.
Assessment of the Co-combustion Process of Ammonia with Hydrogen in a Research VCR Piston Engine
Oct 2022
Publication
The presented work concerns experimental research of a spark-ignition engine with variable compression ratio (VCR) adapted to dual-fuel operation in which co-combustion of ammonia with hydrogen was conducted and the energy share of hydrogen varied from 0% to 70%. The research was aimed at assessing the impact of the energy share of hydrogen co-combusted with ammonia on the performance stability and emissions of an engine operating at a compression ratio of 8 (CR 8) and 10 (CR 10). The operation of the engine powered by ammonia alone for both CR 8 and CR 10 is associated with either a complete lack of ignition in a significant number of cycles or with significantly delayed ignition and the related low value of the maximum pressure pmax. Increasing the energy share of hydrogen in the fuel to 12% allows to completely eliminate the instability of the ignition process in the combustible mixture which is confirmed by a decrease in the IMEP uniqueness and a much lower pmax dispersion. For 12% of the energy share of hydrogen co-combusted with ammonia the most favorable course of the combustion process was obtained the highest engine efficiency and the highest IMEP value were recorded. The conducted research shows that increasing the H2 share causes an increase in NO emissions for both analyzed compression ratios
Green Hydrogen Based Power Generation Prospect for Sustainable Development of Bangladesh using PEMFC and Hydrogen Gas Turbine
Feb 2023
Publication
Bangladesh focuses on green energy sources to be a lesser dependent on imported fossil fuels and to reduce the GHG emission to decarbonize the energy sector. The integration of renewable energy technologies for green hydrogen production is promising for Bangladesh. Hybrid renewable plants at the coastline along the Bay of Bengal Kuakata Sandwip St. Martin Cox’sbazer and Chattogram for green hydrogen production is very promising to solve the power demand scarcity of Bangladesh. Hydrogen gas turbine and hydrogen fuel cell configured power plant performances are studied to observe the feasibility/prospect to the green energy transition. The Plant’s performances investigated based on specification of the plant’s units and verified by MATLAB SIMULINK software. Fuels blending (different percent of hydrogen with fossil fuel/NG) technique makes the hydrogen more feasible as turbine fuel. The net efficiency of the fuel cell-based combined cycle configuration (74%) is higher than that of the hydrogen gas turbine-based configuration (51.9%). Moreover analyses show that the increment of combined cycle gas turbine efficiency (+18.5%) is more than the combined cycle PEMFC configuration (+14%). Long-term storage of renewable energy in the salt cavern as green hydrogen can be a source of energy for emergency. A significant share of power can be generated by a numbers of green power plants at specified places in Bangladesh.
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